Mr Mnangagwa had previously been seen as an heir to the president, but First Lady Grace Mugabe is now the clear front-runner.

The rivalry between Mrs Mugabe and Mr Mnangagwa has split Zanu-PF.Last month, Mrs Mugabe warned of a possible coup plot, saying allies of Mr Mnangagwa were threatening the lives of those who didn't support him.

The Zanu-PF party said Gen Chiwenga's comments were "calculated to disturb national peace... [and] incite insurrection".

The party said it would never succumb to military threats, and that it "reaffirms the primacy of politics over the gun".

The leader of Zanu-PF's youth wing, Kudzai Chipanga, said the general did not have the full support of the entire military.

"It is our country and future at stake and we will not let any individual military man interfere with the leader of the party and legitimately voted president of this country," he told reporters on Tuesday.

The youth wing is a strong supporter of Grace Mugabe.

Gen Chiwenga's warning of possible military intervention came on Monday at a news conference at army headquarters where he was surrounded by senior army officers.

He said the "purging" within Zanu-PF was "clearly targeting members of the party with a liberation background", referring to the country's struggle for freedom from white minority rule.

"We must remind those behind the current treacherous shenanigans that when it comes to matters of protecting our revolution, the military will not hesitate to step in," he said.

Mr Mnangagwa is one such veteran of the 1970s war which ended white minority rule.